Method for the dry-cleaning of additive manufacturing plates

ABSTRACT

A method is provided for dry cleaning a plate used in an additive manufacturing process involving a powder. According to the method, unconsolidated powder is separated from a plate and collected by imposing vibrations on the plate and causing the plate to experience shocks.

The invention falls within the field of powder-based additivemanufacturing by sintering or melting grains of such powder using a beamof energy involving electromagnetic radiation, such as a laser beam forexample, and/or a beam of particles, such as an electron beam forexample.

More specifically, the invention relates to the cleaning of the additivemanufacturing plates and of the components manufactured on these plates.

When an additive manufacturing process is conducted in an additivemanufacturing machine, a first layer of powder is deposited on anadditive manufacturing plate mounted with the ability to slide inside anenclosure surrounding the manufacturing plate. Next, this first layer ofpowder is consolidated according to a predetermined design using one ofthe aforementioned beams of energy. Then, the manufacturing plate islowered within its enclosure so as to allow a second layer of powder tobe deposited and consolidated. Finally, the steps of lowering the plateand then depositing and consolidating layers of powder follow on fromone another until the last layer of powder needed in the manufacture ofthe components that are to be produced has been deposited andconsolidated.

In one disadvantage encountered at the end of this additivemanufacturing process, the component or components manufactured findthemselves immersed in a significant quantity of unconsolidated powderwhich needs to be removed.

According to one method, the manufacturing plate is taken out of themachine, with or without its enclosure, and an operator clears away thegrains of powder by hand, using tools such as a brush and acompressed-air blower or extraction fan.

Because of its essentially manual nature, this first cleaning method isnot really compatible with industrial application.

In addition, this manual cleaning may be dangerous to the operatorbecause the powders used in additive manufacturing generally containtoxic chemical compounds which could be inhaled by the operators inspite of the protective equipment they have.

Finally, according to another disadvantage, if the unconsolidated powderis not kept under a protective atmosphere during cleaning, it has toundergo various processing operations before it can be reused.

For this reason, some manufacturers of additive manufacturing machineshave modified their machines in order better to protect the health ofthe operators and in order to be able to reuse immediately the powderderived from the cleaning of the manufactured components.

For example, the additive manufacturing machine described in Europeanpatent EP1793979 is equipped with means that allow an operator to handleand clean the manufactured parts in the manufacturing enclosure of themachine.

More specifically, these means comprise openings made in a wall of themanufacturing enclosure, a robot arm installed in the manufacturingenclosure, and a suction pipe that can be manipulated in thismanufacturing enclosure. In addition, the openings are fitted withprotective gloves allowing an operator to introduce his hands into themanufacturing enclosure in order to clean the manufactured componentsusing the suction pipe, and the operator can control the robot arm fromoutside the machine in order to move heavier components more easily.

Thanks to the means described in European patent EP1793979, the operatoris protected and the unconsolidated powder is kept under a protectiveatmosphere.

However, the cleaning is still a manual operation requiring the work ofan operator, and because this manual cleaning takes place inside themanufacturing enclosure of the machine, this machine cannot be used formanufacturing further components throughout the duration of thecleaning.

So, European patent EP1192040 makes provision for manufacturing thecomponents in a removable container which can be removed from themanufacturing enclosure of the additive manufacturing machine and takento a cleaning device independent of this machine.

In a first embodiment of this cleaning device, a lid provided with twoopenings facing one another is placed on the top of the container, and acompressed-air source is connected to the first opening while areservoir is connected to the second opening. Thus, and by graduallyraising the manufacturing plate and the manufactured components towardsthe top of the container, the stream of compressed air drives theunconsolidated powder towards the second opening and therefore into thereservoir.

According to one disadvantage of this first embodiment, there is a riskof the powder becoming contaminated with the flow of compressed air usedfor driving the powder towards the reservoir.

In a second embodiment, the top of the container is fitted with a flaredneck comprising a spout allowing the unconsolidated powder to be removedwhen the container is inclined using suitable means and when themanufacturing plate progressively rises.

In this second embodiment, the unconsolidated powder is advantageouslyremoved under gravity to a reservoir. Next, with the reservoir beingequipped with a screen to catch the manufactured components, vibrationsare used to finish off separating the grains of powder from themanufactured components.

While this second embodiment of the cleaning device does not use a flowof compressed air liable to contaminate the unconsolidated powder, itdoes not allow the manufactured components to be cleaned perfectlyeither.

Specifically, under the effect of the vibrations, the finest grains ofpowder are liable to float up into the air in the form of a cloud andsettle again on the manufactured components once the vibration stops.

In addition, in instances in which the manufactured components havecomplex shapes with cavities liable to contain build-ups of powder,vibration alone is not enough to break up the masses of powder which mayform in these cavities during additive manufacturing.

Finally, the simple use of vibrations does not allow removal of all ofthe grains of powder stuck to the manufactured components in a way that,for example, manual brushing does.

For this reason, the objective of the present invention is to guardagainst at least one of the disadvantages of the devices described inthe documents of the prior art while at the same time allowing cleaningof a manufacturing plate alone or together with the components whichhave been manufactured on this plate and which remain attached to thisplate at the end of the additive manufacturing cycle.

To this end, the subject of the invention is a method for thedry-cleaning of a plate used in additive manufacturing using powder, themethod consisting in separating the unconsolidated powder from the plateand collecting it, and the method comprising the steps which consist inimposing vibrations on the plate and causing the plate to experienceshocks.

By virtue of the application of shocks to the plate, the masses ofpowder liable to form in the cavities of the manufactured componentsbreak up, and by virtue of the application of vibrations, the majorityof the grains of unconsolidated powder are gradually made to detachthemselves from the manufactured components and from the manufacturingplate, falling under gravity off the plate or off the manufacturedcomponents.

For preference, the shocks are imparted in a direction orthogonal to theplane of the plate, whereas the vibrations are imposed in directionssubstantially parallel to the plane of the plate.

In order to clean as completely as possible, vibration steps and shocksteps may be alternated several times over.

In order to reduce the cleaning time, vibration and shock steps may beperformed simultaneously.

In order to make best use, during cleaning, of the effect of gravity onthe grains of unconsolidated powder, the method may comprise a priorstep involving inverting the plate.

In order to cause the grains of unconsolidated powder which may havebecome lodged in hollow parts of the manufactured components to drop,the inclination of the plate may be varied during the vibration stepsand/or the shock steps.

In order to protect operators from the toxicity of certain products usedin additive manufacturing, the cleaning method preferably takes place ina doubly confined volume, the cleaning taking place in a cleaningenclosure which is itself placed inside a confinement enclosure.

With a view to recycling or storing the powder derived from thecleaning, the method further comprises a subsequent step that consistsin removing it from these confined volumes under gravity, and preferablywith the aid of suction.

In order to protect the operators and prevent a cloud of powder fromforming during cleaning, the aforementioned confined volumes aresubjected to additional suction during the cleaning.

Further features and advantages of the invention will become apparentfrom the following description. This description, which is given by wayof non-limiting example, refers to the appended drawings, in which:

FIG. 1 is a schematic view of an additive manufacturing plate that is tobe cleaned, the plate being equipped with a support and with a sleeve,

FIG. 2 is a schematic view from above of a first embodiment of acleaning installation according to the invention, with arrowsillustrating a plate cleaning cycle,

FIG. 3 is a schematic view from above of a first embodiment of acleaning installation according to the invention, with arrowsillustrating the use of the installation according to the invention tosupply an additive manufacturing shop with clean and/or new plates,

FIG. 4 is a schematic view from above of a second embodiment of acleaning installation according to the invention, with arrowsillustrating a plate cleaning cycle and the use of the installationaccording to the invention to supply an additive manufacturing shop withclean and/or new plates,

FIG. 5 is a schematic view from above of a dry-cleaning device accordingto the invention,

FIG. 6 is a schematic front view of a dry-cleaning device according tothe invention, this view also illustrating receipt by the dry-cleaningdevice of an additive manufacturing plate that is to be cleaned,

FIG. 7 is a view of a detail of FIG. 6, this view also illustrating thearrival of the plate that is to be cleaned in the cleaning enclosure ofthe dry-cleaning device,

FIG. 8 is a schematic side view of the cleaning enclosure of thedry-cleaning device according to the invention, this view alsoillustrating the turning-over of the plate that is to be cleaned thatthe invention makes provision for, and

FIG. 9 is also a schematic side view of the cleaning enclosure of thedry-cleaning device according to the invention, but this view moreparticularly illustrates the cleaning of the plate that is to be cleanedby the dry-cleaning device according to the invention.

The present invention relates to the cleaning of additive manufacturingplates 10.

An additive manufacturing plate 10 takes the form of a parallelepipedalsupport, generally made of metal, and a few centimetres high and a fewtens of centimetres long and wide in a plane P10.

As is known, such a plate 10 is used as a support in the manufacture ofthe components that are to be manufactured inside the manufacturingchamber of an additive manufacturing machine. More specifically, theplate is mounted inside a manufacturing enclosure surrounding the platein this manufacturing chamber, and the plate is mounted with the abilityto move in vertical translation in this manufacturing enclosure so as tobe able to be lowered before each further deposit of a layer ofunconsolidated powder.

As shown by FIG. 1, in the context of the present invention, the plate10 is preferably surrounded by a sleeve 12 acting as a manufacturingenclosure inside an additive manufacturing machine.

By being assembled with one another, the plate 10 and the sleeve 12 forma container 15. This container 15 is mounted removably inside anadditive manufacturing machine so that it can be taken out of themanufacturing chamber of this machine together with the manufacturedcomponents 14 and the unconsolidated powder 16 surrounding them.

Advantageously, this container 15 makes it easier for the manufacturedcomponents 14 and the unconsolidated powder 16 to be transported from anadditive manufacturing machine to another device present in an additivemanufacturing shop or to a cleaning installation like the one proposedby the present invention.

The plate 10 is fitted with a support 13 for the purposes of guidanceand automated transfer. This support 13 takes the form of a frame ontowhich a manufacturing plate 10 fits. In order to be held in position bystuds or other types of retractable pin, this support 13 comprises bores17. Finally, this support 13 is equipped with a peripheral sealinggasket 19 to prevent any powder from escaping when the plate 10 and itssupport 13 are moved translationally inside the sleeve 12.

The key objectives of the present invention are to recover, withoutadversely affecting it, the significant amount of unconsolidated powder16 which surrounds the components 14 in a container 15 and to rid themanufactured components 14 and the additive manufacturing plates 10 ofthe grains of unconsolidated powder as much as possible.

To this end, the invention provides an additive manufacturing platecleaning installation 20 as illustrated in FIG. 2.

This installation 20 comprises an inlet lock 22 able to receive a plate10 that is to be cleaned from an additive manufacturing machine,suitable transport means 24 being provided for transporting thecontainer 15, the manufactured components 14 and the unconsolidatedpowder 16, under the best possible conditions, from an additivemanufacturing machine to the inlet lock 22 of the installation.

In order to be able to extract a cleaned plate 10 from the installation,the installation 20 also comprises an outlet lock 26. Because theentirety of the installation 20 is preferably confined within aprotective enclosure 28 partially depicted in FIGS. 2 to 4, the outletlock 26 is made through a wall 30 of this enclosure 28.

As illustrated by the various arrows in FIG. 3, the outlet lock 26 mayalso be used for supplying the installation 20 with new and/or cleanplates 10 from the outside E of the installation, and the inlet lock 22may also be used for extracting clean plates 10 from the cleaninginstallation 20 so as to send them to additive manufacturing machinesvia the transport means 24.

In order to ensure optimal cleaning of the plates 10, the installation20 comprises a dry-cleaning device 32 allowing a plate 10 to be cleanedusing vibrations and shocks in a first confinement enclosure E32, awet-cleaning device 34 allowing a plate 10 to be cleaned using at leastone liquid in a second confinement enclosure E34, and at least oneconveying device allowing a plate 10 to be transported between thedry-cleaning enclosure E32, the wet-cleaning enclosure E34 and theoutlet lock 26 of the installation.

More specifically, the dry-cleaning device 32 seeks to recover themaximum amount of unconsolidated powder without adversely affecting itso that this powder can be reused as soon as possible, without priordrying treatment but with just a screening aimed at keeping control ofthe particle size distribution of the powder thus recycled. Following onfrom this, the wet-cleaning device 34 seeks to perfectly clean themanufactured components 14 and the manufacturing plates 10 by removingall the grains of unconsolidated powder which may remain stuck to thecomponents and to the plates after the dry-cleaning.

In order to obtain perfect cleaning of the manufactured components 14and of the manufacturing plates 10, the wet-cleaning device 34 compriseswithin its enclosure E34 at least one washing station 38 that washes aplate 10 with a cleaning liquid, and at least one rinsing station 40that rinses a plate 10 with a rinsing liquid.

For preference, the washing station 38 takes the form of a tank filledwith cleaning liquid and equipped with means, such as a transducer,allowing very high frequency ultrasound waves, preferably at 20 kHz andpossibly at 45 kHz, to be emitted into this cleaning liquid. Thus, whenthe plate 10 and the components 14 that are to be cleaned are immersedin the cleaning liquid, the ultrasound waves generate, through acavitation phenomenon, microscopic bubbles which implode under theeffect of these same waves, and these implosions create turbulence inthe cleaning liquid and allow the last grains of powder still stuck tothe manufactured components 14 and to their manufacturing plate 10 tobecome detached. Advantageously, the microscopic size of the bubblesallows them to enter the smallest cavities in the manufacturedcomponents 14.

Ideally, the cleaning liquid is an aqueous solution and the rinsingliquid is also an aqueous solution.

To make the washing step easier and improve the quality of the cleaningachieved, the wet-cleaning device 34 may comprise within its enclosureE34, a pre-washing station 42 which is obviously situated upstream ofthe washing station 38.

This pre-washing station 42 may take the form of a tank filled withpre-washing liquid and the pre-washing liquid is preferably an aqueoussolution.

The rinsing station 40 may also act as a drying station and comprisemeans of drying the cleaned plates and the manufactured components 14;these drying means adopting for example the form of a tank fitted with ahot air blower.

With a view to fully automating the installation, the wet-cleaningdevice 34 comprises, within its enclosure E34, conveying means (notdepicted) allowing the plates 10 that are to be cleaned and themanufactured components 14 attached to these plates 10 to be conveyed inan automated manner between the various pre-washing 42, washing 38, andrinsing 40, stations.

In an alternative form of embodiment which has not been illustrated inthe figures, the wet-cleaning device 34 may comprise a single workingchamber in which the plates 10 can be pre-washed, washed and possiblydried, and various storage chambers for storing the plates 10 before,between and/or after these various steps.

As illustrated by FIG. 3, the conveying means of the wet-cleaning device34 also allow new and/or clean plates 10 to be conveyed through theenclosure E34 of the wet-cleaning device 34, without passing via thevarious washing and rinsing stations.

In a first embodiment of the installation which embodiment isillustrated in FIGS. 2 and 3, the installation comprises a firstconveyor 44 allowing plates 10 in the process of being cleaned to betransported from the enclosure E32 of the dry-cleaning device 32 towardsthe enclosure E34 of the wet-cleaning device 34, and a second conveyor46 allowing the cleaned plates 10 to be transported from the enclosureE34 of the wet-cleaning device 34 towards the outlet lock 26 of theinstallation 20.

With a view to using the outlet lock 26 of the installation forintroducing new and/or clean plates 10 to an additive manufacturing shopvia the cleaning installation 20, the second conveyor 46 also allowsplates 10 to be transported from the outlet lock 26 of the installation20 towards the enclosure E34 of the wet-cleaning device 34, and thefirst conveyor 44 also allows plates 10 to be transported from theenclosure E34 of the wet-cleaning device 34 towards the enclosure E32 ofthe dry-cleaning device 32.

When the installation 20 is being used in this way for supplying anadditive manufacturing shop with new and/or clean plates 10, provisionmay be made for these plates 10 to undergo wet cleaning in thewet-cleaning device 34. This then ensures perfect cleaning anddecontamination of these plates 10 before they are used in an additivemanufacturing machine, it being possible for these plates 10 to havebecome contaminated on the outside E of the enclosure 28 of theinstallation 20 during unprotected storage or during manual handling.

In this first embodiment of the installation 20, the two conveyors 44,46 may be belt conveyors.

In a second embodiment of the installation 20, which embodiment isillustrated in FIG. 4, the installation comprises a conveyor 36 allowingplates 10 to be transported from the enclosure E32 of the dry-cleaningdevice 32 towards the outlet lock 26 and vice versa, from the outletlock 26 towards the enclosure E32 of the dry-cleaning device 32, atleast one storage zone 48, 50 for the temporary storage of plates 10,and a manipulator arm 52 allowing a plate 10 to be moved between thedry-cleaning device 32, the wet-cleaning device 34, the conveyor 36 andeach temporary storage zone 48, 50.

More specifically, the conveyor 36 may be a belt conveyor, each storagezone 48, 50 may take the form of an open storage device such as a rack,and the manipulator arm 52 is an articulated arm on the end of whichthere is mounted a device 54 for gripping a plate 10, such as a gripperfor example.

By virtue of the presence of at least one storage zone 48, 50, themanipulator arm 52 makes it possible for example to manage the steps ofdry-cleaning and wet-cleaning various plates 10 while the conveyor 36 isused to transfer clean plates 10 from the outlet lock 26 to thedry-cleaning device 32.

For preference, there are two temporary storage zones 48 and 50, so thatclean plates 10 and plates 10 in the process of being cleaned do nothave to be stored in the one same zone.

Again for preference, the manipulator arm 52 is able to move in rotationabout various horizontal and/or vertical axes so as to move each plate10 from one point to another as quickly as possible.

According to an unillustrated and more economical alternative form ofthis second embodiment, the manipulator arm 52 may be omitted and theconveyor 36 may be arranged in such a way as to perform on its own thetransportation of the plates 10 between the dry-cleaning enclosure E32,the wet-cleaning enclosure E34 and the outlet lock 26 of theinstallation.

In order to perform the dry-cleaning of the plates 10 using shocks andvibrations, the invention proposes a device 32 for the dry-cleaning of aplate 10.

As indicated previously, this dry-cleaning device 32 comprises aconfinement enclosure E32. In order to receive a plate 10 that is to becleaned, this confinement enclosure E32 comprises at least one inletlock 56 and in order to discharge a cleaned plate 10, this confinementenclosure E32 also comprises an outlet lock 58. Advantageously, theinlet lock 56 of the enclosure E32 of the dry-cleaning device 32 is alsothe inlet lock 22 of the installation 20.

Because the dry-cleaning enclosure E32 is formed on the ground S by afront wall 60F, a rear wall 60R, a left lateral wall 62G, a rightlateral wall 62D and a roof P, the inlet lock 56 is made through therear wall 60R of the dry-cleaning enclosure E32, and the outlet lock 58is made through the right lateral wall 62D of the dry-cleaning enclosureE32.

As illustrated in FIG. 5, inside this confinement enclosure E32, thedry-cleaning device 32 comprises receiving means 64 for receiving aplate 10 that is to be cleaned, and a dry-cleaning station 66 fordry-cleaning this plate.

More specifically, the receiving means 64 make it possible to receiveand transport a container 15 formed of a plate 10 that is to be cleaned,of its support 13 and of its sleeve 12.

These receiving means 64 take, for example, the form of a chain conveyor72. This chain conveyor 72 extends horizontally inside the dry-cleaningenclosure E32 and in a longitudinal direction DL parallel to the planesof the lateral walls 62G, 62D of the enclosure E32 and perpendicular tothe front 60F and rear 60R walls of this enclosure. Thus, this chainconveyor 72 allows a container 15 and, therefore, a plate 10 that is tobe cleaned, to be transported from the inlet lock 56 of the enclosureE32 to the dry-cleaning station 66.

In order to make it easier to recover unconsolidated powder 16 containedin a container 15, the dry-cleaning device 32 comprises a secondcleaning enclosure 68 inside its first confinement enclosure E32.

This second cleaning enclosure 68 takes the form of a bell 70 mounted ona base 74, and this base 74 comprises an opening 76 to receive a plate10 that is to be cleaned.

More specifically, the base 74 is substantially planar and rectangular,while the bell 70 has the shape of a pyramid S70 extending about acentral axis A70 perpendicular to the plane P74 of the base 74. Inparallel with that, the opening 76 is of a shape and size that aretailored or can be tailored to suit the shape and size of the plates 10that are to be cleaned.

The pyramid shape of the bell 70 about its central axis A70 makes iteasier for the unconsolidated powder 16 to flow and be recovered whenthis bell 70 is inverted with a plate 10 that is to be cleaned.

In a preferred alternative form of embodiment illustrated in FIGS. 6 to9, the bell 70 comprises a bottom part 70B that is parallelepipedalabout its central axis A70, and a top part 70H that is pyramid-shapedabout its central axis A70, the parallelepipedal bottom part 70Bextending from the base 74 and the pyramid-shaped top part 70H extendingbetween this bottom part 70B and the vertex 78 of the bell 70.

In other alternative forms, the bell may also adopt an entirelypyramidal shape, a partially or entirely conical shape, a partially orentirely frustoconical shape, or any other shape making it possible toform a funnel when the bell 70 is inverted.

In order to control the flow of the unconsolidated powder 16 when thebell 70 is inverted in such a way that its base 74 is situated above itsvertex 78, as illustrated by FIGS. 8 and 9, the vertex 78 of the bell 70takes the form of a pipe 80 fitted with a valve 82 or with any otherflow regulating device.

As has just been indicated, the invention makes provision for the bell70 and the plate 10 to be inverted so that the unconsolidated powder 16surrounding the manufactured component or components 14 can be recoveredinto a container 15.

However, first of all, it is necessary to bring the container 15containing the plate 10 that is to be cleaned and the unconsolidatedpowder 16 that is to be recovered towards the opening 76 of the base 74of the cleaning enclosure 68.

To achieve that, provision is made for the cleaning enclosure 68 to bein an initial position corresponding to a non-inverted position in whichthe bell 70 and its vertex 78 are situated above the base 74. In thisinitial position of the cleaning enclosure 68, the plane P74 of the base74 is substantially horizontal, as illustrated in FIGS. 6 and 7.

Next, the receiving means 64 allow a container 15, and therefore a plate10, to be transported from the inlet lock 56 of the confinementenclosure E32 to opposite the opening 76 of the base 74 of the cleaningenclosure 68 when this cleaning enclosure 68 is in its initial position.

To complement the receiving means 64, the dry-cleaning device 32comprises a lift 84 allowing a plate 10 that is to be cleaned to becarried from the receiving means 64 as far as the opening 76.

For this purpose and as illustrated by FIGS. 6 and 7, this lift 84allows the plate 10 that is to be cleaned and the support 13 thereof, tobe moved in vertical translation T1 inside the sleeve 12 of thecontainer 15. More specifically, with the sleeve 12 extending verticallyheightwise about a central axis A12, the vertical translational movementT1 of the plate 10 and of its support 13 takes place parallel to thecentral axis A12 of the sleeve 12 and towards the upper edge 86 of thesleeve 12.

In parallel with the vertical translational movement T1 applied to theplate 10 and to its support 13, the lift 84 allows the sleeve 12 to bemoved in a vertical translational movement T2 parallel to its centralaxis A12 and towards the base 74 of the cleaning enclosure 68. Thus, theupper edge 86 of the sleeve 12 is pressed firmly against the lower edge88 of the opening 76 of the base 74, thereby making it possible toprevent any unconsolidated powder 16 from escaping when the plate 10rises in the sleeve 12 and as this powder is progressively transferredfrom the container 15 towards the interior volume V68 of the cleaningenclosure 68.

In order to achieve the vertical translational movement T1 of the plate10 and of its support 13, the lift 84 for example comprises a piston 90guided in translational movement inside a body 92 and driven with atranslational movement by a motor 94 and an endless screw 96.

In order to achieve the translational movement T2 of the sleeve 12, thelift 84 for example comprises a plate 98 guided in translationalmovement about the rod 89 of the piston 90 and driven with atranslational movement by compression springs 100 pressed againstanother plate 102 fixed to the body 92.

Advantageously, the plates 98, 102 and the springs 100 are dimensionedand positioned relative to the body 92 and to the piston 90 in such away that translational movement applied to the piston 90 by the motor 94also causes a translational movement of the plate 98 under the action ofthe springs 100.

Once the plate 10 has reached the plane P74 of the base 74, thetranslational movement T1 of the plate is halted, and locking elementssuch as studs 104 immobilize the support 13 in the opening 76 of thebase 74, these studs 104 for this purpose entering the bores 17 providedin the support 13.

Advantageously, in this position of the plate 10 relative to the base74, the peripheral sealing gasket 19 of the support 13 also providessealing between the support 13 and the base 74 and therefore between theplate 10 and the base 74.

When the plate 10 is secured to the base 74, the manufactured componentor components 14 and the unconsolidated powder 16 find themselves insidethe interior volume V68 of the cleaning enclosure 68, and this meansthat it is conceivable for this cleaning enclosure 68 to be inverted sothat the unconsolidated powder 16 can be recovered under gravity and forthe plate 10 and the manufactured component or components 14 to bedry-cleaned.

In order for this inversion to be possible, the cleaning enclosure 68 ismounted with the ability to pivot about an axis A68, preferablyhorizontal.

As illustrated in FIG. 8, when the cleaning enclosure 68 is in itsinverted position, the plane P74 of the base 74 is substantiallyhorizontal. For this reason, the cleaning enclosure 68 is mounted withthe ability to pivot through at least 180° inside the confinementenclosure E32 of the dry-cleaning device 32.

In order to allow the installation to be fully automated, an actuatorsuch as an electric motor 106 allows the enclosure 68 to be driven inrotation about its axis A68.

Advantageously, this actuator 106 makes it possible to control the angleof rotation of the cleaning enclosure 68 about its axis A68, for exampleso as to modify the inclination of the base 74 and therefore of theplate 10 during the dry-cleaning cycle.

When the cleaning enclosure 68 is inverted, the unconsolidated powder 16drops under gravity towards the vertex 78 of the bell 70, thereby makingthis powder easy to recover via the pipe 80.

For preference and as illustrated by FIG. 5, powder recovery means 108that recover powder by suction are connected to the pipe 80 at thevertex of the bell 70 via the valve 82, the suction encouraging the flowof powder in the pipe 80, thereby making it possible to prevent the pipefrom clogging.

In order to suck up the grains of powder from the cloud ofunconsolidated powder 16 that forms in the interior volume V68 of thecleaning enclosure when this enclosure 68 is inverted, the bell 70comprises a suction orifice 110 between its base 74 and its vertex 78,this orifice 110 being connected to means 109 of recovering a cloud ofpowder by suction.

For preference, this orifice 110 is provided mid-way up the height ofthe bell 70. In a preferred alternative form illustrated by FIGS. 6 to9, this orifice 110 is provided in the pyramid-shaped top part 70H ofthe bell 70, but near the parallelepipedal bottom part 70B.

In order to collect any grains of powder that might escape from acontainer 15 while it is being transported between the inlet lock 56 ofthe confinement enclosure E32 and the cleaning enclosure 68, or from theenclosure 68 when it is inverted for example, the means 109 forrecovering a cloud of powder by suction are also connected to theinterior volume V32 of the confinement enclosure E32 of the dry-cleaningdevice 32.

Compared with the means 108 of recovering powder by suction, the means109 of recovering a cloud of powder by suction offer a higher suctionflow rate.

In order to seal the cleaning enclosure 68 hermetically after it hasbeen inverted with the plate 10 that is to be cleaned, this cleaningenclosure 68 comprises a door 112 that allows the opening 76 of the base74 to be closed off. This door 112 is mounted with the ability to pivotwith respect to the base 74 and closes off the enclosure 68 just behindthe plate 10 and its support 13. In order to fully automate theinstallation, the moving of this door 112 is also fully automated.

Thanks to the inverting of the cleaning enclosure 68 and of the plate 10that is to be cleaned and to the pyramid-shaped part 70H of thisenclosure 68, a large proportion of the unconsolidated powder 16 can besimply recovered under gravity via the vertex 78 of the bell 70 andpreferably using suction.

However, despite this inversion and this suction, some grains ofunconsolidated powder 16 may still adhere to the plate 10 and to themanufactured component or components 14, particularly when thesecomponents 14 have cavities and/or hollow shapes.

For this reason, in order to cause the grains of powder still adheringto the plate 10 or contained in the hollows or cavities of themanufactured components 14 to drop off, the dry-cleaning station 66 ofthe dry-cleaning device 32 comprises means 114 able to impose vibrationson the plate 10 that is to be cleaned and means 116 able to cause thisplate 10 to experience shocks. As shown in FIGS. 8 and 9, these means114 able to impose vibrations and these means 116 able to impart shocksare supported by the base 74 of the cleaning enclosure 68 and providednext to the opening 76 receiving the plate 10 that is to be cleaned.

More specifically, the means 114 able to impose vibrations for exampleadopt the form of an electric motor vibrator 118 and the means 116 ableto apply shocks adopt for example the form of a pneumatic striker 120.

In order to prevent the vibrator 118 and the striker 120 from spreadingvibrations and shocks into the base 74 and into the cleaning enclosure68 in its entirety, this vibrator 118 and this striker 120 are mountedon a plate 122 which is mounted on suspension rubbers facing an opening124 made in the base 74. Advantageously, sealing means 126, such asgaiters are provided between the base 74 and the plate 122.

As shown by FIG. 9, the vibrator 118 and the striker 120 come directlyinto contact with the plate 10, making it possible to improve theeffectiveness of the cleaning and optimize the use of the vibrations andof the shocks.

Because the dry-cleaning station 66 is situated some distance away fromthe opening 76 receiving the plate 10 that is to be cleaned, thecleaning enclosure 68 comprises internal means 128 of conveying a plate10 between its opening 76 and the means 114, 116 of the dry-cleaningstation 66.

In a preferred alternative form illustrated in FIGS. 8 and 9, theseinternal means 128 of conveying a plate comprise at least a firstguiding support 130, capable of translational movement, a second guidingsupport 132, connected to the plate 122 supporting the means 114, 116 ofthe dry-cleaning station 66, and transfer means 136 transferring a plate10 from the first support 130 to the second support 132.

More specifically, the first support 130 is mounted with the ability tomove translationally inside the cleaning enclosure 68, facing theopening 76 of the base 74 and its translational movement T3 is in adirection perpendicular to the plane P74 of the base, for example underthe effect of an actuating cylinder 134.

In its raised position illustrated in FIG. 8, the first support 130 isable to receive the plate 10 that is to be cleaned. Once the enclosure68 and the plate 10 have been inverted, the first support 130 is able toreceive the plate 10 inverted, which means to say with the manufacturedcomponent or components 14 underneath the plate 10. For this purpose,the first support 130 takes the form of a plurality of fingers 138,spaced apart from one another and a few centimetres long.Advantageously, the fingers 138 are rounded so as to avoid powder grainretention.

Once the plate 10 has been received by the first support 130, this firstsupport is moved in a translational movement from its raised position toa lowered position illustrated in FIG. 9 allowing the plate 10 that isto be cleaned to be transferred to the second guiding support 132.

As the second support 132 also takes the form of a plurality of fingers140 spaced apart from one another and a few centimetres long, preferablyof rounded shape, the means 136 of transferring a plate 10 take the formof a fork 142 guided in a translational movement between the firstsupport 130 and the second support 132. The translational movement T4 ofthis fork 142 is in a direction parallel to the plane P74 of the base74, and for example under the effect of an actuating cylinder 144. Thisfork 142 allows the plate 10 that is to be cleaned to be grasped in sucha way as to cause it to slide from the fingers 138 of the first support130 to the fingers 140 of the second support 132.

There may also possibly be provided an intermediate guide support 146between the first support 130 and the second support 132, thisintermediate support 146 also being formed of fingers 148, preferablyhaving a rounded shape.

Once the plate 10 is present on the second support 132, the dry-cleaningby shocks and vibrations intended by the invention can take place.However, and prior to the application of vibrations and shocks, the rod150 of an actuating cylinder 152 supported by the plate 122 of thedry-cleaning station 66 clamps the plate 10 to the second support 132.

According to the invention, the application of vibrations to a plate 10involves causing the plate 10 to oscillate at frequencies of between 40and 150 Hz, the amplitudes of the oscillations of the plate 10 notexceeding 5 millimetres.

In the preferred alternative form of embodiment illustrated in FIGS. 8and 9, the vibrations are generated by the vibrator 118 and transmittedto the plate 10 and to the manufactured component or components 14 viathe plate 122 and the second support 132.

Still according to the invention, the shock are efficaciously applied toa plate 10 and therefore to the manufactured component or components 14by a moving body having a kinetic energy of 20 to 25 Joules as it comesinto contact with the plate 10. In addition, a plate 10 experiences aplurality of shocks at frequencies of between 15 and 25 Hz, namely from120 to 600 shocks during the course of a dry-cleaning cycle, to give aball-park figure.

In the preferred alternative form of embodiment illustrated in FIGS. 8and 9, the shocks are efficaciously applied to the plate 10 by the rod154 of the striker 120.

By virtue of the application of shocks to the plate 10, the masses ofunconsolidated powder grains 16 liable to form in the cavities or hollowshapes of the manufactured components 14 break up, and by virtue of theapplication of vibrations, these grains of powder are extracted from thehollow shapes or cavities of the manufactured components 14 and fallunder gravity towards the vertex 78 of the bell 70.

Once the cycle of induction of vibrations and application of shocks isover, the plate 10 is conveyed towards the outlet lock 58 of thedry-cleaning device 32 where it may, for example, be picked up by thegripping device 54 so as to be removed from the enclosure E32, asillustrated by FIG. 5.

In order to return from the dry-cleaning station 66 to the outlet lock58 and, more specifically, as far as the receiving means 64, the cleanedplate 10 follows the same path as when it arrived, but in the oppositedirection.

More specifically, once the clamping of the rod 154 has been released,the fork 142 returns the plate 10 from the second support 132 to thefirst support 130, then the first support 130 returns to the raisedposition so as to bring the plate 10 back into the opening 76 of thebase 74. Next, the cleaning enclosure 68 is returned to its non-invertedinitial position, after having taken care to open the door 112, so thatthe plate 10 is recovered by the lift 84 and its piston 90 whichfinishes conveying the cleaned plate 10 as far as the chain conveyor 72of the receiving means 64.

By virtue of its complete automation, the cleaning installation 20 isparticularly well suited to being installed in an additive manufacturingshop comprising a plurality of additive manufacturing machines.

Advantageously, the installation 20, and more particularly thedry-cleaning device 32, may be designed to clean a plate 10 on its own,namely without a sleeve 12 forming a container 15 with this plate 10.

In addition, the installation 20 and the plates 10 may also be designedin such a way as to avoid the use of supports 13 for the plates 10.

Advantageously, the two, confinement E32 and cleaning 68, enclosures ofthe dry-cleaning device 32 afford twofold confinement, best protectingindividuals from the toxicity of certain additive manufacturing powders.

More generally, the present invention also relates to a method for thedry-cleaning of an additive manufacturing plate 10 which may for examplebe implemented using the dry-cleaning device 32 which has just beendescribed.

According to the invention, this method consists in separating theunconsolidated powder 16 from a plate 10 and in collecting it byimposing vibrations on the plate and by subjecting the plate to shocks.

As indicated hereinabove, the vibrations applied to the plate 10 havefrequencies preferably of between 40 and 150 Hz, and the amplitudes ofthe oscillations of the plate 10 under the effect of the vibrations donot exceed 5 millimetres.

In addition, a plurality of shocks are efficaciously applied to a plate10 with the aid of a moving body having a kinetic energy of 20 to 25Joules as it comes into contact with the plate 10.

For preference, the shocks are applied in a direction orthogonal to theplane P10 of the plate 10, and for example using the rod 154 of thestriker 120. Specifically, since a plate 10 is designed to beparticularly rigid in its width and in its length, it is more effectiveto apply these shocks perpendicularly to the plate 10 and therefore inits height.

For preference, a plate 10 experiences from 120 to 600 shocks during thecourse of a dry-cleaning cycle, at frequencies of between 15 and 25 Hz.

In order to encourage the grains of unconsolidated powder 16 to dropunder gravity from the hollow shapes or cavities of the manufacturedcomponent or components 14, the vibrations are preferably imposed on theplate 10 in directions substantially parallel to the plane P10 of theplate 10, and for example using a vibrator 118.

Again, in order to encourage the cleaning of the plate 10 and of themanufactured components, the vibrations may be imposed on the plate 10in directions that are substantially parallel to the plane P10 of theplate 10, but different from one another. For preference, the vibrationsare imposed on the plate 10 in two directions that are parallel to theplane P10 of the plate 10 but perpendicular to one another andcorrespond for example to the directions extending along the length andalong the width of the plate 10. This combination of vibrations indifferent directions is advantageous because it allows the manufacturedcomponents and their cavities to be best rid of the grains ofunconsolidated powder regardless of the directions in which thesecomponents and these cavities extend parallel to the plane P10 of theplate.

With a view to optimal dry-cleaning, vibration steps and shock steps arealternated a number of times over.

Vibration steps and shock steps may potentially be performedsimultaneously and to reduce the dry-cleaning cycle time.

For example, thanks to the cleaning enclosure 68 and the fact that it ismounted with the ability to rotate about a horizontal axis A68, themethod comprises a prior step that consists in inverting the plate 10,this inverting allowing a large proportion of the unconsolidated powder16 to be recovered under gravity.

Still with a view to optimal dry-cleaning and encouraging the grains ofunconsolidated powder 16 to drop under gravity from the hollow shapes orcavities of the manufactured component or components 14, thedry-cleaning method may make provision to vary the inclination of theplate 10 during the steps of inducing vibrations in and/or the steps ofapplying shocks to the plate 10.

For example, by virtue of the cleaning enclosure 68, the dry-cleaningmethod is carried out in a confined volume V68, preferably a volume thatis doubly confined by virtue of the confinement enclosure E32 of thedry-cleaning device 32.

Under gravity, or using means 108 for recovering powder by suction, thedry-cleaning method comprises a step subsequent to the inducing ofvibrations and the application of shocks which consists in removing fromthis confined volume V68 the grains of unconsolidated powder 16 derivedfrom the dry-cleaning of the plate 10, for example so that it can bestored and reused.

Advantageously, the suction intended for the recovery of theunconsolidated powder 16 that is dropped into the vertex 78 of the bell70 is in operation for only a few seconds.

For example by virtue of the means 109 of recovering a cloud of powderwhich are connected to the dry-cleaning enclosure 68, the method makesprovision for the confined volume V68 to be subjected to additionalsuction during cleaning, this additional suction having the intendedpurpose of eliminating any clouds of powder that might form inside thedry-cleaning enclosure 68 during a dry-cleaning cycle.

For preference, the additional suction is at least maintained in thedry-cleaning enclosure 68 during the vibrating of a plate 10 and duringthe application of shocks to the plate 10.

Finally and, for example by virtue of the means 109 of recovering acloud of powder which are connected to the confinement enclosure E32 ofthe dry-cleaning device 32, the method makes provision for theconfinement volume V32 of the dry-cleaning device 32 also to besubjected to additional suction.

It may be noted that the dry-cleaning device 32 inverts and cleans onlythe plate 10 and the manufactured components attached to this plate 10.Specifically, there is no benefit in inverting and cleaning the sleeve12 because the translational movement of the plate 10 with its support13 and the sealing gasket 19 is enough to rid the internal walls of thesleeve 12 of any grains of unconsolidated powder. In addition, invertingthe sleeve 12 with the plate 10 would represent an additional, andtherefore unnecessary, power consumption.

According to one advantage, the dry-cleaning device 32 allows the plate10 and the manufactured components to be separated from the sleeve 12 soas to transfer only the plate 10 and the manufactured components to thewet-cleaning device 34. This is because wet-cleaning of the sleeves 12is unnecessary.

1-11. (canceled) 12: A method for dry cleaning a plate used in anadditive manufacturing process involving a powder, the method comprisingsteps of: separating unconsolidated powder from a plate to be cleaned,the separating step including substeps of: imposing vibrations on theplate, and causing the plate to experience shocks; and collecting theunconsolidated powder separated from the plate in the separating step.13: The method according to claim 12, wherein the shocks are imparted ina direction orthogonal to a plane of the plate. 14: The method accordingto claim 12, wherein the vibrations are imposed in directionssubstantially parallel to a plane of the plate. 15: The method accordingto claim 12, wherein the substeps of imposing vibrations and causing theplate to experience shocks are alternated repeatedly a plurality oftimes. 16: The method according to claim 12, wherein the substeps ofimposing vibrations and causing the plate to experience shocks areperformed simultaneously. 17: The method according to claim 12, furthercomprising a step of inverting the plate prior to the separating step.18: The method according to claim 12, wherein, during at least one ofthe substeps of imposing vibrations and causing the plate to experienceshocks, an inclination of the plate is varied. 19: The method accordingto claim 12, wherein the separating step and the collecting step areperformed in a confined space. 20: The method according to claim 19,further comprising a step of, after the collecting step, removing theunconsolidated powder separated from the plate from the confined spaceusing gravity. 21: The method according to claim 20, wherein, in theremoving step, the unconsolidated powder separated from the plate isremoved from the confined volume using gravity and by suction. 22: Themethod according to claim 19, wherein the confined volume is subjectedto suction.